Advances in the development and improvements of the luminous flux of light-emitting devices such as solid-state semiconductor and organic light-emitting diodes (LEDs) have made these devices suitable for use in general illumination applications, including architectural, entertainment, and roadway lighting. Light-emitting diodes are becoming increasingly competitive with light sources such as incandescent, fluorescent, and high-intensity discharge lamps.
One challenge frequently encountered when developing LED-based light sources resides in the development of adequate cooling means for the LEDs comprised therein. For instance, since the performance of LEDs is generally sensitive to temperature, and variations therein, temperature dissipation and control often becomes an important design parameter. In particular, light sources combining a plurality of LEDs in a relatively tight configuration, for instance to provide higher output intensities or combined emission spectra, may require careful light source configuration design to enhance temperature management.
In the manufacture of laser diode arrays, and particularly stacked diode bar arrays, modular configurations have been proposed that combine a series of diode bars intercalated between a corresponding series of thermally conductive spacers that provide respective heat sinks and electrical connection for the diode bars. This configuration facilitates testing of the individual modules and the replacement thereof when defective, and generally provides additional structural support for the diode bars leading to improved emission properties. The modules are combined and driven in series to provide a substantially narrowband high output light source for use, for example, as an optical pump for solid state lasers. Examples of such laser diode arrays are proposed in various forms and configurations in U.S. Pat. No. 4,454,602 issued Jun. 12, 1984 to Smith, U.S. Pat. No. 5,325,384 issued Jun. 28, 1994 to Herb et al., U.S. Pat. No. 5,394,426 issued Feb. 28, 1995 to Joslin, U.S. Pat. No. 5,835,515 issued Nov. 10, 1998 to Huang, U.S. Pat. No. 6,195,376 issued Feb. 27, 2001 to Wilson et al., U.S. Pat. No. 6,352,873 issued Mar. 5, 2002 to Hoden et al., and U.S. Pat. No. 6,768,753 issued Jul. 27, 2004 to Treusch.
LED-based light sources currently used, for example, in general purpose illumination applications, generally combine one or more surface emitting LEDs to provide a desired luminous effect. For instance, these surface emitting LEDs may be mounted in groups or arrays to provide illumination at one or more wavelengths that may, if appropriately configured, be combined to provide a desired output spectrum or pattern. LED-based light sources providing such combined outputs may be used, for example, as a white light source (e.g., combining red, green and blue (RGB) LEDs, red, amber, green and blue (RAGB) LEDs, etc.), as a patterned or multicolour light source, or as a light source of a desired or variable output spectrum.
Various examples of such general purpose LED-based light sources are provided in U.S. Pat. No. 7,048,412 for an Axial LED Source, issued May 23, 2006 to Martin et al., wherein the proposed light sources comprise a number of LEDs disposed along facets of a light source axis and radiating outwardly therefrom toward a collector disposed to collect and redirect the emitted light to produce a desired luminous effect. Other such general purpose LED-based light sources, generally comprising LED arrays disposed perpendicularly to the light source axis, are also illustrated therein.
In these and other available general purpose LED-based light sources, the surface emitting LEDs used are generally configured to provide a first large light-emitting surface and an opposite surface from which heat generated by the LED is dissipated through a heat sink or the like. For high output light sources, however, the above surface emitting configuration often leads to various heat management and/or cooling difficulties that affect the overall performance of the light source.
Consequently, there is a need for improved light sources, comprising LEDs and/or other such light-emitting elements, that overcome at least some of the drawbacks of known light sources.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.